Currently, mobile communication systems such as cellular phone systems and wireless metropolitan area networks (MANs) are widely used. Meanwhile, in order to increase the speed and capacity of radio communication, lively discussions have been taking place about the next-generation mobile communication technology.
In many mobile communication systems, a radio relay apparatus for relaying radio communication is provided between a base station apparatus and mobile communication apparatuses. The provision of the radio relay station apparatus makes it possible to cover areas (dead spots) where radio communication is difficult due to blockage by buildings or the like, increase the size of the cell managed by the base station apparatus, and improve the throughput. Some of such radio relay apparatuses manage cells that are independent from the cell managed by a base station apparatus, and behave like a base station toward mobile communication apparatuses. For example, a method has been proposed that assigns to a cell of a radio relay apparatus a cell ID different from that of a base station apparatus. Thus, a mobile communication apparatus will not be aware of whether the cell to be accessed is a cell of the relay station apparatus or a cell of a base station apparatus (see, for example, 3rd Generation Partnership Project (3GPP), “Further Advancements for E-UTRA Physical Layer Aspects (Release 9)”, TR 36.814 V1.5.0, Section 9, November 2009).
With regard to a radio network where radio communication is performed via a plurality of nodes, there has been proposed a technique in which a node transmits a sub-frame including broadcast information to another node. This sub-frame includes information such as identification information of the node, the transmission power level of the node, and route information from a core node (base station apparatus) to the node (see, for example, Japanese Laid-open Patent Publication No. 2008-109614, paragraphs [0025] through [0027]).
A problem with this technique is that, in some cases, the mobile communication apparatus is unable to appropriately control communication performed via a radio relay apparatus unless the mobile communication apparatus determines whether the destination node is a base station apparatus or a radio relay apparatus.
For instance, in the case where the number of radio resources available to the relay station apparatus is less than the number of radio resources available to the base station apparatus, the mobile communication apparatus preferably performs communication control taking this restriction into account. This also applies to the case where the timing at which radio communication between the radio relay apparatus and the mobile communication apparatus is not performed is determined in advance so as to prevent radio interference. Further, in the case where the transmission power of the relay station apparatus is different from that of the base station apparatus, the mobile station apparatus preferably performs quality measurement taking the difference in the transmission power into account. Furthermore, because the transmission delay time between the base station apparatus and the mobile communication apparatus varies depending on whether communication is performed via the relay station apparatus, the mobile station apparatus preferably performs delay control taking the presence of the radio relay station apparatus into account.